Derek's Scratch Built 74" 3D Plane

[Graham Lawrie]

Very cool Derek:) I wonder if the motor is powerful enough for such a big bird:) Cant wait to see the maiden:) Good Luck:)

[Derek]

Very cool Derek:) I wonder if the motor is powerful enough for such a big bird:) Cant wait to see the maiden:) Good Luck:)

I"ve seen some other builds, using this motor, that are very similar to my plane. However, those builds were actual "kits". I would imagine that the kit's weigh less than my build. I have no idea "how much" less. I still need to weigh my plane. I am confident that my plane will get off the ground and fly circuits. Loops, rolls, etc may be out of the question....I just have no way of knowing right now.

[pvolcko]

Thought you had a cool prop thrust measuring rig? Super slippery linear bearing you dad provided? If the thust is at least as good as the weight you'll be A-OK.

[Derek]

Thought you had a cool prop thrust measuring rig? Super slippery linear bearing you dad provided? If the thust is at least as good as the weight you'll be A-OK.

I forgot all about that linear bearing that Dad had. Thanks for the reminder, Paul! I'll see if I can borrow that again.

[Derek]

I've completely forgotten to ask my Dad if I can borrow that linear bearing. "Life" has me pretty busy right now. However, I got some time, tonight, to come up with a battery tray to hold the two 6S packs and they are located directly in front of, and slightly above, the Castle 120HV....so, it will be very easy to make the battery connection to the ESC. I've not calibrated the ESC yet. It's a task that I've not done on such a large ESC (on such a large model) and I want to be sure that I do it properly...meaning when I'm better rested (and perhaps my Dad on hand, too, to lend a second opinion). So, I'll get to that later.

But....as the CG is obviously a big concern (rightfully so), I 'kinda-sorta" checked the CG. With the batteries in place and everything connected (the wings not connected), I lifted the plane by the wing spar tube....the nose tipped downwards. I have to say that I was pleasantly surprised and delighted to see that. I can't imagine the addition of the two wings will have much of an effect. Yes, they will add a bit of weight behind the CG (wing spar tube) because there is more material rearwards of the spar tube in the wings, but I can't imagine there will be a major negative effect.

I'll put the wings on the plane this weekend and I'll get a weight measurement and make some adjustments, if needed, for a slightly nose heavy CG.

Then it's just a matter of calibrating the ESC and, when "Life" allows, the maiden flight.

I did some more checking around on the net for other threads and videos about people using the Tacon Bigfoot 160 motor on their large models. I wanted to see what props are being used on what planes with various AUW. Most people seem to running this motor with a 10S setup and 22" props but their models are surely much lighter than mine. one review I read had a guy stating that he was, in fact, running this motor with a 12S setup and a 20x8 prop (I have a 20x10) on a 38lbs plane. That's quite promising. I couldn't find any video of that plane, unfortunately. However, I am encouraged to read that a few people are running this motor in similar fashions to mine.

[pvolcko]

Can't wait to see this one!